1. Field of the Invention
This invention relates to an apparatus and a method for sanitary mixing of viscous materials and, more particularly, to sanitary mixing of water and cross-linked polyacrylamide (CPAM) to form a hydrogel for use as a filler in implanted prostehesis.
2. Background Information
Highly viscous materials find many uses, including uses in the. Materials prepared for food, drug and cosmetic use must be prepared in a sanitary manner in compliance with Food and Drug Administration requirements. The material must be protected from outside contamination and be prepared in equipment having cleanable, non-reactive surfaces.
Conventional techniques for the sanitary preparation of highly viscous materials often involves preparation of the material in one device and then transfer of the material to another device for dispensing. For example, one method of manufacturing implantable prosthetic devices filled with a cross-linked polyacrylamide hydrogel requires hydration of the polyacrylamide in one device and then transfer to a pressure dispensing device for injection into the prosthetic shells.
One of the difficulties posed by the preparation of highly viscous, cohesive materials is that they will cling to the walls of the devices used in preparation. This complicates dispensing the prepared material and cleaning the preparation equipment after use.
It is also desirable to be able to prepare materials without exposing them to the atmosphere. This prevents exposure to air borne contaminants. In certain applications, it is desirable to prevent entraining air in the material. For example, air entrained in gels used in implantable prosthesis undesirably reduces radiolucency.
Accordingly, there is a need for a device which allows the preparation of highly viscous materials in a sanitary manner protected from contamination and entrainment of air and which allows the dispensing of prepared material without the need to transfer the material into another vessel.